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I read this article on Space.com and I quote "As far as we know, that's as far [back] as we can see — we get an image of the universe as it was when it was about 389,000 years old," So what I wanna know is that

  1. How can we look into the past?
  2. Does this mean that we might be able to see ourselves even?
Qmechanic
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Muhammad Fahad
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3 Answers3

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How can we look into the past?

Light has a fixed velocity of almost 300.000 meters per second. Sunlight takes about 8 minutes to reach us. So we see the sun always 8 minutes ago.

As the other answer says, stars are much further away and it takes light that much longer to reach us.

How do we know how far away the stars are? There are various methods that clever astronomers have found to measure this distance.

Once we know the distance we know the time that light left that star, so a time "map" of the constelations can be made.

Does this mean that we might be able to see ourselves even?

Not even as a hypothesis, as you are here, not on a star distance to be radiating light towards the earth.

anna v
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Stars are very far away. So light takes a while to get from stars to you. The light arriving now shows you what the stars looked like when the light left.

It is like getting a letter from a far away friend. The letter took a few days to arrive. It has news from a few days ago.

mmesser314
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You go outside at night and you look at the sky. That's the universe and that's the past streaming in on you. With your own eyes, of course, you can't see much farther than approx. 2.5 million years back - the Andromeda galaxy is easily seen, even though it's not as pretty as in astrophotographs: https://en.wikipedia.org/wiki/Andromeda_Galaxy. What you will see with the unaided eye is a much darker version of this: http://www.docdb.net/img/dso/ngc/2/ngc_224_m31_ot.jpg, but it is visible and I look at it several times a year just for the fun of it.

Get a small (but good) telescope and you can see much further... probably up to 2 billion years back in time: http://www.uitti.net/stephen/astro/essays/farthest_naked_eye_object.shtml.

Get a smallish radio telescope (maybe 3m in diameter) and you can "see all the way" by observing the cosmic microwave radiation. It's certainly something that dedicated amateurs could pull off without too much difficulty (and probably have).

PS: No, you can not see yourself... after all, you weren't there, in the past.

CuriousOne
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